Cooling means for axial fans



a. c. POL;

COOLING MEANS FOR AXIAL FANS Aug. 15, 1950 Filed 001;. 8, 1947 A10 ATTORNEY Patented Aug. 15, 1950 2 ,518,815 1 t t COOLING MEANS FOR; AXIAL Gilbert C. Polk, Detroit, Mich, assignor to Amen ican Blower Corporation, Dearborn, corporation of Delaware Mich; a

Application. October 8, 1947; SeriaINo. 778,584

5 Claims. (Cl. 230-209) Thisinvention relates to new and useful improvementsj in cooling means for axial fans.

"One of the objects of this invention is to provide a new and improved axial fan for transfer-rin hot-gases.

Another object is to provide a fan casing embodying ameans for cooling th fan shaft support when transferring hot gases.

Another-objectis toprovide a cooling means for axial fans which is inexpensive and simply constructed; V

Other objects will become apparentfrom time totime throughout the specification and claims as hereinafter related.

In the' accompanying'drawing, to be taken as a part of this specification, there isclearly and fully 'illustrated a preferred embodiment of this invention, in which drawing:

The figure shown illustrates an axial fan and casing therefor taken vertical section and embodying this invention.

Referring to the drawing by characters of reference there is an axial or propeller type fan I comprising a fan casing 2" having a pair of inlets dand 4 and anoutl-et 5 for axial discharge. The fan casing 2 has a wall 6 and aperture 1 opposite the out1et5; Thereis a depressed wall member portion 8 in the formof a cup-shaped or irustroeconical member closing the aperture I and" joined to'the casing wall 6 as to be an in- I tegral part thereof. The depressed wall portion 8 extends into the casing 2 forming a cavity or frustro-conical chamber 9 and has an aperture I through its smaller base through which extends a fan shaft II. The fan shaft II has fan blades I2 (shown diagrammatically) at its extremity positioned in the entrance portion to the outlet and directed for discharge of gases into the outlet 5. Positioned in the cavity or chamber 9 is a fan shaft supporting member I3 which is carried by bracket members I4 attached to the depressed wall portion 8. The supporting member l3 may be a bearing for supporting the fan shaft II or it may be the motor which drives the fan. Positioned Within the casing 2 around and spaced from the depressed wall portion 8 is an insulating member I5 of similar shape (cupshaped or frustro-conical) which is joined to the casing as at Hi. The insulating member I5 has an aperture I! for the fan shaft II, the fan blades I2 being positioned slightly beyond the end Wall of the insulating member I5. The insulating member I5 encloses an annular conical space l8 and has a plurality of apertures I9 around the base portion thereof.

In operation this invention functions as 01- lows: This axial or propeller type fan is designed to "transfer hot gases and the cooling means herein described function to prevent the fan shaft supporting member I3 (motor or bearing) from overheating. When the fan blades I2 are rotated, the hot gases are drawn through the inlets 3 and land discharged axially through the outlet 5; Thereis during operation of the fan a low pressure space on the suction side of the fan which will cause air to be drawn from the space i8 through the apertures I9. This suction of air from the space I8 will cause air to be drawn through the cavity 9 around the supporting member 13 and into the space I8 through the aperture I i) surrounding the fan shaft It thus providing a continuous circulation of cooling air to prevent overheating of the supporting member I3-. This circulation of air inaddition to positive cooling of the supporting member I3 provides furtherprote'ction against overheating in that it sets up a secondary insulating layer of cool air within the space I8 thereby further decreasing the outward flow of heat from Within the casing 2 to the supporting member I3;

l-l'a'ving thus described the invention what is claimed and isdesired to be secured by Letters Patent of the United States is:

1. An axial fan for transferring hot gases comprising a casing having an inlet and an axial outlet, said casing having a wall opposite said outlet having a depressed portion forming a cavity therein, said depressed wall portion having an aperture therethrough, an insulating Wall member surrounding and spaced from said depressed Wall portion and having an aperture alined with said first-named aperture, a fan shaft extending through said apertures into the interior of said casing, said shaft carrying fan blades directed towards said outlet, a supporting member for said shaft positioned in said cavity and carried by said depressed wall portion, said insulating wall member being operable to decrease th flow of heat toward said supporting member; and said insulating wall member and said depressed wall portion each having one or more apertures 0perable by fan suction to cause air to be conducted through said cavity and over said supporting member for cooling the same and through the space around said depressed wall portion and within said insulating wall member to provide a layer of insulating air around said cavity, and to discharge said air to the suction side of said fan blades.

2. An axial fan for transferring hot gases comprising a casing having an inlet and an axial outlet, said casing having a Wall opposite said outlet having a depressed portion extending into said casing and forming a cavity therein, said depressed wall portion having an aperture therethrough substantially concentric with said outlet, an insulating wall member surrounding and spaced from said depressed wall portion and having an aperture alined with said first-named aperture, a fan shaft extending through said apertures into the interior of said casing, said shaft carrying fan blades at the extremity thereof directed towards said outlet, a supporting member for said shaft positioned in said cavity and carried by said depressed wall portion, said insulating wall member being operable to decrease the flow of heat toward said supporting member; said insulating wall member having a plurality of apertures around the base portion thereof, and the suction of said fan being operable to draw cooling air through said first-named aperture from around said supporting member and through the space between said wall portion and said insulating member, the flow of air through said last-mentioned space providing a layer of moving air as additional insulation against the outflow of heat to said cavity.

3.In an axial fan for transferring hot gases, cooling means for a fan shaft supportingmember comprising a fan casing having an inlet and an outlet, a casing wall opposite said outlet having a depressed portion forming a cavity operable to contain a fan shaft supporting member, an insulating wall member within said casing spaced from and surrounding said depressed wall portion, said insulating member being operable to decrease the flow of heat to said cavity, an aperture in said depressed wall portion opening from said cavity into the space enclosed by said insulating wall member, a plurality of apertures in said insulating wall member such that a differential of air pressure between said cavity and the interior of said casing will cause flow of cooling ai from said cavity through said apertures and the space between said wall portion and said wall member.

cavity, said insulating member ,being operable to decrease flow of heat to said cavity, one or more apertures in said insulating member opening from said space to the suction side of said gas I moving means and forming with said cavity, said 4. In a fan for transferring hot gases, cooling means for a fan shaft supporting member comopening and said space, an air flow passageway, and said gas moving means being operable to draw air through said passageway for cooling said supporting member, the air flow through said space providing a cooling layer of moving air as additional insulation against the outflow of heat from said casing to said cavity.

5. In a fan for transferring hot gases, a fan casing having a side wall opening, a, conical wall member within said casing and having its base portion secured to said casing around said opening, said wall membe forming a. cavity having an air flow opening at its inner end, a fan shaft supporting member in said cavity, a conical wall member of insulating material within said casing and surrounding said first-named wall member in spaced relation thereto, said second-named wall member having its base sealed to said-casing and having a plurality of circumferentially spaced air flow openings therethrough adjacent the Wall of said casing such that said first-named and said second-named flow openings and the space between said wall members form a conical air flow passageway surrounding said cavity.

GILBERT C. POLK.

REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS Switzerland Sept. 15, 1931 

